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  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <script>
    //   let arr = ["a", "b", "c"];
      // arr.name = 'jack';
    //   for (const key in arr) {
    //     //   console.log(typeof key);
    //       console.log(key);
    //   }

      let obj = {
          name:'jack',
          11:55,
          age:90
      };
      for (const v in obj) {
          console.log(v);
      }
    //   let myArr = [2, 6, 8, 9, 5,5];
    //   myArr.forEach((item) => {
    //     if (item % 2 !== 0) {
    //       return;
    //     // 不能使用continue和break进行跳出;
    //     }
    //     console.log("item:" + item);
    //   });
    // for (const myFor of myArr) {
    //     console.log(myFor);
    // }
    // for (const myFor2 of Object.keys(obj)) {
    //     console.log(myFor2);
    // }
    // console.log(Object.keys(obj));
    </script>
  </body>
</html>
